NET INCOME PER SHARE (Basic and Diluted Net Income Per Share) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Basic net income per share:
Net income	$ 13,211	$ 11,243	$ 28,418	$ 23,429
Weighted average common shares outstanding (in shares)	28,446	28,583	28,403	29,234
Basic net income per common share (in dollars per share)	$ 0.46	$ 0.39	$ 1.00	$ 0.80
Diluted net income per share:
Net income	$ 13,211	$ 11,243	$ 28,418	$ 23,429
Weighted average common shares outstanding (in shares)	28,446	28,583	28,403	29,234
Effect of dilutive securities:
Stock options and restricted stock (in shares)	331	446	226	586
Weighted average common shares for diluted earnings per share (in shares)	28,777	29,029	28,629	29,820
Diluted net income per common share (in dollars per share)	$ 0.46	$ 0.39	$ 0.99	$ 0.79